This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. An understanding of the historical interaction between pathogens and host immunity is essential to a clear view of contemporary disease dynamics. The public record of United States telegraphic case reports is an extensive and unexploited resource that we will use to fill an important gap in our understanding of pre-vaccine influenza and pertussis dynamics. Using a previously developed database and web-based user interface, we will digitize case reports of influenza and whooping cough morbidity and influenza mortality from states and cities for 1930 - 1950. The aim of this project is to assess the magnitude and significance of waning immunity to influenza and pertussis prior to mass vaccination. Both of these diseases continue to cause significant morbidity and mortality, partly due to pathogen evolution or an imperfect immune response. We will develop a parsimonious between-host model of disease transmission using a flexible representation of waning immunity. We will assess model sensitivity to alternative assumptions about waning immunity and test model predictions against pre-vaccine data. Public databases are important collaborative tools in data-driven biological sciences. This case report database, along with the subsequent analysis and modeling fills a critical gap in host-pathogen research that complements existing bioinformatics databases and research of human microparasites.